#   python if
print("---------------------IF---------------------------------")
age = 6
if age >= 18:
    print('your age is', age)
    print('adult')
else:
    print('your age is ', age)
    print('teenager')
print("------------------------------------------------------")
age = 3
if age >= 18:
    print('your age is', age)
    print('adult')
elif age >= 6:
    print('teenager')
else:
    print('your age is ', age)
    print('kid')
print("------------------------------------------------------")
str_age = input('birth:')
age = int(str_age)  # 返回的数据类型是str，str不能直接和整数比较，必须先把str转换成整数。Python提供了int()
if age >= 18:
    print('your age is', age)
    print('adult')
elif age >= 6:
    print('teenager')
else:
    print('your age is ', age)
    print('kid')
